1/* 2 * An SPI driver for the Philips PCF2123 RTC 3 * Copyright 2009 Cyber Switching, Inc. 4 * 5 * Author: Chris Verges <chrisv@cyberswitching.com> 6 * Maintainers: http://www.cyberswitching.com 7 * 8 * based on the RS5C348 driver in this same directory. 9 * 10 * Thanks to Christian Pellegrin <chripell@fsfe.org> for 11 * the sysfs contributions to this driver. 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License version 2 as 15 * published by the Free Software Foundation. 16 * 17 * Please note that the CS is active high, so platform data 18 * should look something like: 19 * 20 * static struct spi_board_info ek_spi_devices[] = { 21 * ... 22 * { 23 * .modalias = "rtc-pcf2123", 24 * .chip_select = 1, 25 * .controller_data = (void *)AT91_PIN_PA10, 26 * .max_speed_hz = 1000 * 1000, 27 * .mode = SPI_CS_HIGH, 28 * .bus_num = 0, 29 * }, 30 * ... 31 *}; 32 * 33 */ 34 35#include <linux/bcd.h> 36#include <linux/delay.h> 37#include <linux/device.h> 38#include <linux/errno.h> 39#include <linux/init.h> 40#include <linux/kernel.h> 41#include <linux/string.h> 42#include <linux/slab.h> 43#include <linux/rtc.h> 44#include <linux/spi/spi.h> 45 46#define DRV_VERSION "0.6" 47 48#define PCF2123_REG_CTRL1 (0x00) /* Control Register 1 */ 49#define PCF2123_REG_CTRL2 (0x01) /* Control Register 2 */ 50#define PCF2123_REG_SC (0x02) /* datetime */ 51#define PCF2123_REG_MN (0x03) 52#define PCF2123_REG_HR (0x04) 53#define PCF2123_REG_DM (0x05) 54#define PCF2123_REG_DW (0x06) 55#define PCF2123_REG_MO (0x07) 56#define PCF2123_REG_YR (0x08) 57 58#define PCF2123_SUBADDR (1 << 4) 59#define PCF2123_WRITE ((0 << 7) | PCF2123_SUBADDR) 60#define PCF2123_READ ((1 << 7) | PCF2123_SUBADDR) 61 62static struct spi_driver pcf2123_driver; 63 64struct pcf2123_sysfs_reg { 65 struct device_attribute attr; 66 char name[2]; 67}; 68 69struct pcf2123_plat_data { 70 struct rtc_device *rtc; 71 struct pcf2123_sysfs_reg regs[16]; 72}; 73 74/* 75 * Causes a 30 nanosecond delay to ensure that the PCF2123 chip select 76 * is released properly after an SPI write. This function should be 77 * called after EVERY read/write call over SPI. 78 */ 79static inline void pcf2123_delay_trec(void) 80{ 81 ndelay(30); 82} 83 84static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr, 85 char *buffer) 86{ 87 struct spi_device *spi = to_spi_device(dev); 88 struct pcf2123_sysfs_reg *r; 89 u8 txbuf[1], rxbuf[1]; 90 unsigned long reg; 91 int ret; 92 93 r = container_of(attr, struct pcf2123_sysfs_reg, attr); 94 95 if (strict_strtoul(r->name, 16, ®)) 96 return -EINVAL; 97 98 txbuf[0] = PCF2123_READ | reg; 99 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); 100 if (ret < 0) 101 return -EIO; 102 pcf2123_delay_trec(); 103 return sprintf(buffer, "0x%x\n", rxbuf[0]); 104} 105 106static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr, 107 const char *buffer, size_t count) { 108 struct spi_device *spi = to_spi_device(dev); 109 struct pcf2123_sysfs_reg *r; 110 u8 txbuf[2]; 111 unsigned long reg; 112 unsigned long val; 113 114 int ret; 115 116 r = container_of(attr, struct pcf2123_sysfs_reg, attr); 117 118 if (strict_strtoul(r->name, 16, ®) 119 || strict_strtoul(buffer, 10, &val)) 120 return -EINVAL; 121 122 txbuf[0] = PCF2123_WRITE | reg; 123 txbuf[1] = val; 124 ret = spi_write(spi, txbuf, sizeof(txbuf)); 125 if (ret < 0) 126 return -EIO; 127 pcf2123_delay_trec(); 128 return count; 129} 130 131static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm) 132{ 133 struct spi_device *spi = to_spi_device(dev); 134 u8 txbuf[1], rxbuf[7]; 135 int ret; 136 137 txbuf[0] = PCF2123_READ | PCF2123_REG_SC; 138 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), 139 rxbuf, sizeof(rxbuf)); 140 if (ret < 0) 141 return ret; 142 pcf2123_delay_trec(); 143 144 tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F); 145 tm->tm_min = bcd2bin(rxbuf[1] & 0x7F); 146 tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */ 147 tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F); 148 tm->tm_wday = rxbuf[4] & 0x07; 149 tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */ 150 tm->tm_year = bcd2bin(rxbuf[6]); 151 if (tm->tm_year < 70) 152 tm->tm_year += 100; /* assume we are in 1970...2069 */ 153 154 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 155 "mday=%d, mon=%d, year=%d, wday=%d\n", 156 __func__, 157 tm->tm_sec, tm->tm_min, tm->tm_hour, 158 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 159 160 /* the clock can give out invalid datetime, but we cannot return 161 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 162 */ 163 if (rtc_valid_tm(tm) < 0) 164 dev_err(dev, "retrieved date/time is not valid.\n"); 165 166 return 0; 167} 168 169static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) 170{ 171 struct spi_device *spi = to_spi_device(dev); 172 u8 txbuf[8]; 173 int ret; 174 175 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 176 "mday=%d, mon=%d, year=%d, wday=%d\n", 177 __func__, 178 tm->tm_sec, tm->tm_min, tm->tm_hour, 179 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 180 181 /* Stop the counter first */ 182 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 183 txbuf[1] = 0x20; 184 ret = spi_write(spi, txbuf, 2); 185 if (ret < 0) 186 return ret; 187 pcf2123_delay_trec(); 188 189 /* Set the new time */ 190 txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC; 191 txbuf[1] = bin2bcd(tm->tm_sec & 0x7F); 192 txbuf[2] = bin2bcd(tm->tm_min & 0x7F); 193 txbuf[3] = bin2bcd(tm->tm_hour & 0x3F); 194 txbuf[4] = bin2bcd(tm->tm_mday & 0x3F); 195 txbuf[5] = tm->tm_wday & 0x07; 196 txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */ 197 txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100); 198 199 ret = spi_write(spi, txbuf, sizeof(txbuf)); 200 if (ret < 0) 201 return ret; 202 pcf2123_delay_trec(); 203 204 /* Start the counter */ 205 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 206 txbuf[1] = 0x00; 207 ret = spi_write(spi, txbuf, 2); 208 if (ret < 0) 209 return ret; 210 pcf2123_delay_trec(); 211 212 return 0; 213} 214 215static const struct rtc_class_ops pcf2123_rtc_ops = { 216 .read_time = pcf2123_rtc_read_time, 217 .set_time = pcf2123_rtc_set_time, 218}; 219 220static int __devinit pcf2123_probe(struct spi_device *spi) 221{ 222 struct rtc_device *rtc; 223 struct pcf2123_plat_data *pdata; 224 u8 txbuf[2], rxbuf[2]; 225 int ret, i; 226 227 pdata = kzalloc(sizeof(struct pcf2123_plat_data), GFP_KERNEL); 228 if (!pdata) 229 return -ENOMEM; 230 spi->dev.platform_data = pdata; 231 232 /* Send a software reset command */ 233 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 234 txbuf[1] = 0x58; 235 dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n", 236 txbuf[0], txbuf[1]); 237 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 238 if (ret < 0) 239 goto kfree_exit; 240 pcf2123_delay_trec(); 241 242 /* Stop the counter */ 243 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 244 txbuf[1] = 0x20; 245 dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n", 246 txbuf[0], txbuf[1]); 247 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 248 if (ret < 0) 249 goto kfree_exit; 250 pcf2123_delay_trec(); 251 252 /* See if the counter was actually stopped */ 253 txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1; 254 dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n", 255 txbuf[0]); 256 ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8), 257 rxbuf, 2 * sizeof(u8)); 258 dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n", 259 rxbuf[0], rxbuf[1]); 260 if (ret < 0) 261 goto kfree_exit; 262 pcf2123_delay_trec(); 263 264 if (!(rxbuf[0] & 0x20)) { 265 dev_err(&spi->dev, "chip not found\n"); 266 goto kfree_exit; 267 } 268 269 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n"); 270 dev_info(&spi->dev, "spiclk %u KHz.\n", 271 (spi->max_speed_hz + 500) / 1000); 272 273 /* Start the counter */ 274 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 275 txbuf[1] = 0x00; 276 ret = spi_write(spi, txbuf, sizeof(txbuf)); 277 if (ret < 0) 278 goto kfree_exit; 279 pcf2123_delay_trec(); 280 281 /* Finalize the initialization */ 282 rtc = rtc_device_register(pcf2123_driver.driver.name, &spi->dev, 283 &pcf2123_rtc_ops, THIS_MODULE); 284 285 if (IS_ERR(rtc)) { 286 dev_err(&spi->dev, "failed to register.\n"); 287 ret = PTR_ERR(rtc); 288 goto kfree_exit; 289 } 290 291 pdata->rtc = rtc; 292 293 for (i = 0; i < 16; i++) { 294 sprintf(pdata->regs[i].name, "%1x", i); 295 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR; 296 pdata->regs[i].attr.attr.name = pdata->regs[i].name; 297 pdata->regs[i].attr.show = pcf2123_show; 298 pdata->regs[i].attr.store = pcf2123_store; 299 ret = device_create_file(&spi->dev, &pdata->regs[i].attr); 300 if (ret) { 301 dev_err(&spi->dev, "Unable to create sysfs %s\n", 302 pdata->regs[i].name); 303 goto sysfs_exit; 304 } 305 } 306 307 return 0; 308 309sysfs_exit: 310 for (i--; i >= 0; i--) 311 device_remove_file(&spi->dev, &pdata->regs[i].attr); 312 313kfree_exit: 314 kfree(pdata); 315 spi->dev.platform_data = NULL; 316 return ret; 317} 318 319static int __devexit pcf2123_remove(struct spi_device *spi) 320{ 321 struct pcf2123_plat_data *pdata = spi->dev.platform_data; 322 int i; 323 324 if (pdata) { 325 struct rtc_device *rtc = pdata->rtc; 326 327 if (rtc) 328 rtc_device_unregister(rtc); 329 for (i = 0; i < 16; i++) 330 if (pdata->regs[i].name[0]) 331 device_remove_file(&spi->dev, 332 &pdata->regs[i].attr); 333 kfree(pdata); 334 } 335 336 return 0; 337} 338 339static struct spi_driver pcf2123_driver = { 340 .driver = { 341 .name = "rtc-pcf2123", 342 .bus = &spi_bus_type, 343 .owner = THIS_MODULE, 344 }, 345 .probe = pcf2123_probe, 346 .remove = __devexit_p(pcf2123_remove), 347}; 348 349static int __init pcf2123_init(void) 350{ 351 return spi_register_driver(&pcf2123_driver); 352} 353 354static void __exit pcf2123_exit(void) 355{ 356 spi_unregister_driver(&pcf2123_driver); 357} 358 359MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); 360MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); 361MODULE_LICENSE("GPL"); 362MODULE_VERSION(DRV_VERSION); 363 364module_init(pcf2123_init); 365module_exit(pcf2123_exit); 366